What are the potential consequences of hypothermia in a newborn baby?

A Method to Provide Neuroprotection After Hypoxic Ischemic Encephalopathy

What are the potential consequences of hypothermia in a newborn baby?

Complications of Hypothermia

The nurse's position at the bedside affords the first line of intervention when complications arise in the infant with HIE undergoing cooling therapy. An intimate understanding of what to anticipate and the transient changes in baseline monitoring parameters are needed. Several complications also occur as a result of asphyxia and/or hypothermia (see Table 4). Bradycardia may also occur but subsides when the infant is warmed slightly. Monitoring for other cardiac arrhythmias is also necessary, as these have been reported.[4,5,27]

Hypotension may also occur secondary to hypovolemia, reduced cardiac output, and reduced stroke volume. A reduced blood flow and hyperviscosity have been reported in the hypothermic infant, which poses a potential risk for microembolism, but evidence does not show the cooled infant to suffer more emboli than the other infants.[4]

Coagulation is prolonged during hypothermia, but if the coagulation is normal before cooling, the infant should not experience problems as a result of the cooling therapy. It is not unusual, however, for the asphyxiated patient to have abnormal clotting studies secondary to hypoxic injury to the liver. Monitoring of liver function tests (LFTs) as well as other clotting studies would be indicated at regular intervals. The nurse will also be cognizant of physical signs of coagulopathy, such as petechiae; oozing from heelsticks or venipuncture sites; or bloody urine, gastric secretions, or endotracheal secretions.

Any infant who had a traumatic delivery should especially be monitored for bleeding, especially subgaleal hemorrhages. Trauma to the head would contraindicate selective head cooling and aggressive management of the bleeding with administration of fresh frozen plasma, cryoprecipitate, blood, and volume, as indicated. Electrolytes should be monitored closely to maintain reference ranges, and the bedside expert should be knowledgeable regarding normal laboratory values. Monitoring of blood glucose levels to avoid excess at each end of the spectrum is important to meeting basic metabolic and nutritional needs.[27,30] Attention to the urinary output is discussed above. The risk for seizures and skin complications is discussed in later sections of this article. Side effects often resolve or return to baseline with the return to normothermic temperature, as discussed in the rewarming section. Of note, most side effects did not interfere with the management of providing hypothermia during clinical trials. Described protective benefits far outweighed potential side effects.[2,26,27]

NAINR. 2011;11(3):113-124. © 2011 Elsevier Science, Inc.

Cite this: Neonatal Hypothermia - Medscape - Sep 01, 2011.

  • Abstract and Introduction
  • Incidence and Impact of HIE
  • Pathophysiology of HIE
  • Previous Research Using Animal Models
  • Predictors of Hypoxic Injury
  • Understanding the Concept of Neuroprotection
  • Clinical Trials
  • Implications for Nursing
  • Preparing for Hypothermia: The Nurse's Role
  • Nursing Care of the Patient Receiving Hypothermia
  • Complications of Hypothermia
  • The Role of aEEG After HIE
  • Developmental Considerations
  • Complications of the Integument System
  • Considerations for Management of Pain and Discomfort
  • Pain Evaluation for the Infant After Hypoxia: A Complicated Assessment
  • Seizure Management
  • Rewarming: Slowly Achieving a Normothermic Temperature
  • Nutritional Support
  • Parental Concerns
  • Long-term Developmental Outcomes
  • Conclusion
  • References

Table 1.  Summary of Initial Clinical Trials; Seminal Work From 3 Primary Research Teams

CitationSample Size/Inclusion CriteriaMethod/Duration of CoolingFollow-upFindings
27 234 term infants; 116 randomly selected for cooling and 118 selected for control. Sixteen infants were lost to follow-up at 18 months with final reported sample; cooled, n = 108 and control, n = 110.Clinical inclusion criteria: Apgar score of five or less at 10 minutes after birth; continued need for resuscitation at 10 minutes after birth; pH <7 or base deficit of 16 mmol/L and evidence of moderate or severe encephalopathy (Sarnet score) and aEEG recording used to control for the severity of injury. Method: Head cooling with cooling cap within 6 hours of birth. Duration of cooling: 72 hours at 34°C–35°C (measured rectally). Followed up infants until 18 months of age with neurologic, visual, auditory, and neurodevelopmental assessments by a developmental specialist using the Bayley II scale. No differences were reported in the frequency of clinically significant complications. Head cooling in the most severely affected infants had little effect on mortality rates as well as measured short- and long-term outcomes. The most significant improvements in the rates of mortality and short- and long-term neurodevelopmental outcomes were noted in the moderately affected infants.
31 Six participating sites enrolled a total of 65 infants; randomized patients to groups: 32 to hypothermia (treatment) and 33 to normothermia (control).A total of five patients were withdrawn from the study (three from treatment and two from control). Inclusion criteria included infants >35 weeks gestation and >2 kg birth weight and within 6 hours of birth who exhibited one clinical sign (acidosis, Apgar, prolonged resuscitation, bradycardia >15 minutes) of HIE and two neurologic findings (posturing, seizures, tone abnormalities orchanges in level of consciousness [LOC]). Method: Whole body cooling with infant cooling blanket within 6 hours of birth. Duration of cooling: 72 hours at 34°C–35°C (measured rectally). Primary outcome variables were death or abnormal neurodevelopmental scores (Bayley II), Cognitive Adaptive Test/Clinical Linguistic and Auditory Milestone Scale (CAT/CLAMS), or Vineland examinations up to and including 12 months of age. 77% of all infants enrolled were classified as Sarnat III (severe). The death rate was 31% in the treatment group and 42% in the control group (P = .35). The patients evaluated at 12 months (17 treatment and 12 control patients ) had neurodevelopmental testing, which showed that 24% of the treatment group had severely abnormal index scores compared with 64% of the control group. Length of hospitalization was not significantly different between the groups.
14 Hypothermia group, n = 106; control group, n = 102 of 239 eligible infants; and three infants from the control group were lost to follow-up.Infants >36 weeks gestation admitted to the hospital by 6 hours of age who demonstrated severe acidosis (pH ≤7, cord or infant blood analysis with base deficit of 16 mmol/L and/or 10 minutes Apgar score ≤5 with prolonged resuscitation requirement at delivery. Neurologic evaluation for moderate or severe (modified Sarnat) encephalopathy was used. Exclusion criteria: admission >6 hours, major congenital abnormality, intrauterine growth restriction (IUGR), low birth weight <1800 grams, or parental/attending physician refusal. Method: Whole body cooling with infant cooling blanket within 6 hours of birth. Duration of cooling: 72 hours at 33.5°C (target temp) (measured with esophageal and skin probes). Rewarming process; increased infant's temperature by 0.5°C per hour until goal temperature of 36.5°C. Followed up infants until 18–22 months of age with an assessment of neuromotor disability based on the presence of cerebral palsy (CP) and functional disability graded according to the Gross Motor Function Classification System. Cognitive outcome assessment was completed with the Bayley Scales of Infant Development II.Moderate disability was defined as Gross Motor Function Classification System (GMFCS) grade of level 2, hearing impairment, or persistent seizure disorder. Primary outcome was death or disability (moderate or severe). There was no increased risk of death or disability as a result of the treatment protocol. There was no increased rate of moderate or severe disability at 18–22 months of age with the rate of CP among the hypothermia group, 19%, and control group, 30%. The Bayley II index less than 70 was 25% in the hypothermia group and 39% in the control group. Whole body hypothermia reduced the risk of death or disability in those infants who were identified as moderate or severe classification of HIE. The safety of this treatment (whole-body hypothermia) was also proven.

Eicher, Wagner et al. 2005; Gluckman, Wyatt et al. 2005; Shankaran, Laptook et al. 2005.

Table 3.  Recommended Inclusion/Exclusion Criteria for Hypothermia Treatment After HIE

Inclusion Criteria:
Infants >36 weeks of age
Infants who have been evaluated as moderate or severe HIE/Sarnat stages II or III (see Table 2)
Blood gas pH <7 and/or base deficit of >16 (cord gas or initial blood gas)
History of acute perinatal event and/or Apgar score at 10 minutes of <5
Need for continued respiratory support through ventilation
Exclusion criteria
Infants with birth weight <2 kg
Infants who have been evaluated as mild HIE/Sarnat stage I (see Table 2)
Life-threatening coagulopathy
Longer than (>) 6 hours from birth
Medical team exclusion for other reasons (may include family request or other physical/genetic anomalies)

Eicher et al, 2005; Gluckman et al, 2005; Shankaran et al, 2005.

Authors and Disclosures

Katherine M. Newnam, MS, RN, CPNP, NNP-BC and Donna L. DeLoach, MS, RN, CPNP, NNP-BC

Neonatal Intensive Care Unit, Children's Hospital of the King's Daughters, 601 Children's Lane, Norfolk, VA 23507.

Address correspondence to
Katherine M. Newnam, MS, RN, CPNP, NNPBC, Neonatal Nurse Practitioner, Neonatal Intensive Care Unit, Children's Hospital of the King's Daughters, 601 Children's Lane, Norfolk, VA 23507. E-mail: .

Why are newborn babies at risk of hypothermia?

Neonates are prone to rapid heat loss and consequent hypothermia because of a high surface area to volume ratio, which is even higher in low-birth-weight neonates. There are several mechanisms for heat loss: Radiant heat loss: Bare skin is exposed to an environment containing objects of cooler temperature.

What are the complications of hypothermia?

Complications of hypothermia are as follows:.
Cardiac arrhythmias at temperatures below 30-32°C..
Infection..
Aspiration pneumonia..
Pulmonary edema..
Pancreatitis..
Bleeding diathesis..
Bladder atony..
Frostbite..